Non-isothermal pyrolysis kinetics characteristics of ZhaoTong lignite using thermogravimetric analysis

In this study, the effects of heating rate and ash content on the pyrolysis kinetic characteristics of ZhaoTong lignite were investigated by using thermogravimetric analysis (TGA) method. The non-isothermal pyrolysis process of lignite was strongly affected by the heating rate and ash content. Raw lignite was treated by demineralization method, indicating that with increasing the demineralizing time, carboxyl groups content of lignite increased, while hydroxyl content and minerals content of lignite decreased, respectively. The pyrolysis kinetics characteristics of lignite such as the activation energy (E) and frequency factor (A) were discussed by Coats-Redfern method. The first-order reaction kinetics model had the higher linear fitting correlation on the non-isothermal pyrolysis reaction of lignite. The activation energy of lignite pyrolysis increased with increasing heating rate, but decreased with increasing ash content. The study can provide the theoretical foundation for large-scale pyrolysis of lignite.

Automated summary

This study investigated the effects of heating rate and ash content on the pyrolysis kinetic characteristics of ZhaoTong lignite using thermogravimetric analysis (TGA) method. It was found that the non-isothermal pyrolysis process of lignite was strongly influenced by the heating rate and ash content. The demineralization treatment of raw lignite resulted in an increase in carboxyl groups content and a decrease in hydroxyl content and minerals content. The pyrolysis kinetics characteristics, such as activation energy (E) and frequency factor (A), were discussed using the Coats-Redfern method. The study also showed that the activation energy of lignite pyrolysis increased with increasing heating rate, while it decreased with increasing ash content. These findings provide a theoretical foundation for the large-scale pyrolysis of lignite.